In vitro metabolism of midazolam, triazolam, nifedipine, and testosterone by human liver microsomes and recombinant cytochromes P450: Role of CYP3A4 and CYP3A5
In vitro metabolism of midazolam, triazolam, nifedipine, and testosterone by human liver microsomes and recombinant cytochromes P450: Role of CYP3A4 and CYP3A5
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DOI：
10.1124/dmd.31.7.938
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发表时间：
2003-07-01
影响因子：
3.9
通讯作者：
Greenblatt, DJ
中科院分区：
文献类型：
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作者：
Patki, KC;von Moltke, LL;Greenblatt, DJ
咪达唑仑、三唑仑（TRZ）、睾酮和硝苯地平均已被广泛用作CYP 3A体外代谢的探针。我们使用这四种底物来评估CYP 3A 4和CYP 3A 5对人肝微粒体（HLM）和重组酶体外生物转化的贡献。重组CYP 3A 4和CYP 3A 5（rCYP 3A 4和rCYP 3A 5）均从咪达唑仑和三唑仑产生1-OH和4-OH代谢物，从睾酮产生6 β-羟基睾酮，从硝苯地平产生氧化硝苯地平。总体而言，CYP 3A 5的代谢活性低于CYP 3A 4。酮康唑有效抑制HLM和rCYP 3A 4中咪达唑仑、三唑仑、睾酮和硝苯地平代谢产物的形成。对于所有四种底物，酮康唑在rCYP 3A 5中的抑制效力约为rCYP 3A 4的5- 19倍。在睾酮相互作用研究中，睾酮抑制HLM和rCYP 3A 4中1-OH-TRZ的形成，但显著激活4-OH-TRZ的形成，但不激活rCYP 3A 5。在rCYP 3A 4中，睾酮抑制氧化硝苯地平的形成。然而，在rCYP 3A 5中，睾酮在较低浓度下轻微激活氧化硝苯地平的形成，然后抑制。因此，CYP 3A 4和CYP 3A 5均有助于HLM中的咪达唑仑、三唑仑、睾酮和硝苯地平生物转化，CYP 3A 5的代谢活性通常低于CYP 3A 4。由于酮康唑在rCYP 3A 5中的抑制效力显著低于rCYP 3A 4和HLM，因此在涉及酮康唑和CYP 3A底物的药物相互作用中，CYP 3A 5的重要性可能低于CYP 3A 4。
Midazolam, triazolam (TRZ), testosterone, and nifedipine have all been widely used as probes for in vitro metabolism of CYP3A. We used these four substrates to assess the contributions of CYP3A4 and CYP3A5 to in vitro biotransformation in human liver microsomes (HLMs) and in recombinant enzymes. Recombinant CYP3A4 and CYP3A5 (rCYP3A4 and rCYP3A5) both produced 1-OH and 4-OH metabolites from midazolam and triazolam, 6beta-hydroxytestosterone from testosterone, and oxidized nifedipine from nifedipine. Overall, the metabolic activity of CYP3A5 was less than that of CYP3A4. Ketoconazole potently inhibited midazolam, triazolam, testosterone, and nifedipine metabolite formation in HLMs and in rCYP3A4. The inhibitory potency of ketoconazole in rCYP3A5 was about 5- to 19-fold less than rCYP3A4 for all four substrates. In testosterone interaction studies, testosterone inhibited 1-OH-TRZ formation, but significantly activated 4-OH-TRZ formation in HLMs and rCYP3A4 but not in rCYP3A5. Oxidized nifedipine formation was inhibited by testosterone in rCYP3A4. However, in rCYP3A5, testosterone slightly activated oxidized nifedipine formation at lower concentrations, followed by inhibition. Thus, CYP3A4 and CYP3A5 both contribute to midazolam, triazolam, testosterone, and nifedipine biotransformation in HLMs, with CYP3A5 being metabolically less active than CYP3A4 in general. Because the inhibitory potency of ketoconazole in rCYP3A5 is substantially less than in rCYP3A4 and HLMs, CYP3A5 is probably less important than CYP3A4 in drug-drug interactions involving ketoconazole and CYP3A substrates.